This thesis analyses the financial plans for the retirement section of the Norwegian national insurance system, by asking why it was impossible to finance a retirement plan providing two-thirds of the income of a normal industrial worker. The process of establishing a national insurance system (folketrygden) began soon after Prime Minister Einar Gerhardsen promised the electorate a retirement plan providing two-thirds of a normal worker’s salary. The problem is addressed over three sections. In the first section it asks if the financial plans that were established shortly after Gerhardsen’s promise could realistically have funded the promised pension, by comparing the cost estimates and assumptions made with the actual development for the period that was forecasted. The results from the analysis come to a clear and unambiguous conclusion that the plans were realistic, and were based on a robust presumption. The costs estimate for disability allowances that had a shared financial plan with the retirement scheme in the national Thinsurance system were on the other hand grossly underestimated. In the next section the paper analyses how new political legislation radically altered the national insurance system by incorporating allowances for injuries, unemployment and (most importantly) sickness into the national insurance system (folketrygden). In addition, the retirement age was lowered and the minimum retirement payout was increased. During this process social factors played an increasingly important role, while the commitment to maintain the promised retirement income of two-thirds of a worker’s salary dwindled. The third section of the thesis evaluates the consequences of the new political legislation that was enacted after 1966. The inclusion of new allowances with a stronger focus on social factors made the national insurance system unable to meet its financial obligations in 1972. In order to solve the problem a new budget for the national insurance system (folketrygden) was established in the summer of 1972 to bring costs under control. During the 1970s the mechanisms that regulated the level of the retirement payout were continuously changed in an inconsistent and confusing process, but without enacting any legislation to lower the level of retirement payout. The consequences that followed from this process were such that by 1980 the level of retirement payout was significantly lower than the promised two-thirds of a normal salary of an industrial worker.